Merge lp:~alan-griffiths/mir/fix-1717061 into lp:mir

[Alan Griffiths]

Clamp the window aspect ratio dimensions (to avoid ldiv0) and define default window settings in one place. (LP: #1717061)

[Mir CI Bot (mir-ci-bot)]

FAILED: Continuous integration, rev:4254
https://mir-jenkins.ubuntu.com/job/mir-ci/3662/
Executed test runs:
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-mir/5011/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-0-fetch/5240
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=artful/5228
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=xenial/5228
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=zesty/5228
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=artful/5054
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=artful/5054/artifact/output/*zip*/output.zip
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=zesty/5054/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=artful/5054
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=artful/5054/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/5054
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/5054/artifact/output/*zip*/output.zip
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=zesty/5054/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=artful/5054
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=artful/5054/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=zesty/5054
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=zesty/5054/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/5054
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/5054/artifact/output/*zip*/output.zip

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review: Needs Fixing (continuous-integration)

[Mir CI Bot (mir-ci-bot)]

FAILED: Continuous integration, rev:4256
https://mir-jenkins.ubuntu.com/job/mir-ci/3663/
Executed test runs:
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-mir/5012/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-0-fetch/5241
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=artful/5229
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=xenial/5229
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=zesty/5229
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=artful/5055
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=artful/5055/artifact/output/*zip*/output.zip
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=zesty/5055/console
    ABORTED: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=artful/5055/console
    ABORTED: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/5055/console
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=zesty/5055/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=artful/5055
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=artful/5055/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=zesty/5055
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=zesty/5055/artifact/output/*zip*/output.zip
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/5055/console

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review: Needs Fixing (continuous-integration)

[Gerry Boland (gerboland)]

+unsigned clamp_dim(unsigned dim)
+{
+ return std::min<unsigned long>(std::numeric_limits<long>::max(), dim);
+}

Why max "long" - the signedness of it confuses me. What is this clamping "dim" to?

If sizeof(unsigned) < sizeof(long), this always returns "dim", so the only interesting case is if sizeof(unsigned) == sizeof(long), where this clamps dim in the bottom 1/2 of the unsigned ints. Intended?

review: Needs Information

[Alan Griffiths (alan-griffiths)]

> +unsigned clamp_dim(unsigned dim)
> +{
> + return std::min<unsigned long>(std::numeric_limits<long>::max(), dim);
> +}
>
> Why max "long" - the signedness of it confuses me. What is this clamping "dim"
> to?
>
> If sizeof(unsigned) < sizeof(long), this always returns "dim", so the only
> interesting case is if sizeof(unsigned) == sizeof(long), where this clamps dim
> in the bottom 1/2 of the unsigned ints. Intended?

That was the intent, yes. To clamp dim to the shared range of long and unsigned int.

[Gerry Boland (gerboland)]

So you want bottom 1/2 only to ensure the sign bit is always positive. Ok

review: Approve

[Mir CI Bot (mir-ci-bot)]

FAILED: Continuous integration, rev:4258
https://mir-jenkins.ubuntu.com/job/mir-ci/3666/
Executed test runs:
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-mir/5017/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-0-fetch/5249
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=artful/5237
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=xenial/5237
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=zesty/5237
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=artful/5060
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=artful/5060/artifact/output/*zip*/output.zip
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=zesty/5060/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=artful/5060
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=artful/5060/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/5060
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/5060/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=zesty/5060
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=zesty/5060/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=artful/5060
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=artful/5060/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=zesty/5060
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=zesty/5060/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/5060
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/5060/artifact/output/*zip*/output.zip

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review: Needs Fixing (continuous-integration)

[Mir CI Bot (mir-ci-bot)]

FAILED: Autolanding.
More details in the following jenkins job:
https://mir-jenkins.ubuntu.com/job/mir-autolanding/1424/
Executed test runs:
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-mir/5020/console
    None: https://mir-jenkins.ubuntu.com/job/generic-land-mp/1555/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-0-fetch/5253
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=artful/5241
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=xenial/5241
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=zesty/5241
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=artful/5063
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=artful/5063/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=zesty/5063
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=zesty/5063/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=artful/5063
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=artful/5063/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/5063
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/5063/artifact/output/*zip*/output.zip
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=zesty/5063/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=artful/5063
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=artful/5063/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=zesty/5063
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=zesty/5063/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/5063
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/5063/artifact/output/*zip*/output.zip

review: Needs Fixing (continuous-integration)

[Mir CI Bot (mir-ci-bot)]

FAILED: Autolanding.
More details in the following jenkins job:
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Executed test runs:
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-mir/5022/console
    None: https://mir-jenkins.ubuntu.com/job/generic-land-mp/1556/console
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-0-fetch/5255
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=artful/5243
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    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=zesty/5243
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=artful/5065
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=artful/5065/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=zesty/5065
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=zesty/5065/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=artful/5065
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=artful/5065/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/5065
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial/5065/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=zesty/5065
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=zesty/5065/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=artful/5065
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=artful/5065/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=zesty/5065
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=cross-armhf,compiler=gcc,platform=mesa,release=zesty/5065/artifact/output/*zip*/output.zip
    FAILURE: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial/5065/console

review: Needs Fixing (continuous-integration)

[Alan Griffiths (alan-griffiths)]

Landing by hand

=== modified file 'debian/changelog'
--- debian/changelog	2017-09-14 09:27:21 +0000
+++ debian/changelog	2017-09-18 08:45:41 +0000
@@ -47,6 +47,8 @@
       . [miral-shell] Don't allow splashscreen to be occluded (LP: #1705973)
       . [miral-shell] Update maximized windows on display changes (LP: #1705695)
       . Make racy DragAndDrop test reliable. (LP: #1704780)
+      . [libmiral] Define default window settings in one place and clamp the
+        actual values to avoid ldiv0. (LP: #1717061)
 
  -- Alan Griffiths <[e-mail]>  Thu, 10 Aug 2017 11:54:30 +0000
 

=== modified file 'src/miral/CMakeLists.txt'
--- src/miral/CMakeLists.txt	2017-09-08 08:45:02 +0000
+++ src/miral/CMakeLists.txt	2017-09-18 08:45:41 +0000
@@ -61,6 +61,7 @@
     window_manager_tools.cpp            ${miral_include}/miral/window_manager_tools.h
                                         ${miral_include}/miral/window_management_policy_addendum2.h
                                         ${miral_include}/miral/window_management_policy_addendum3.h
+                                        window_info_defaults.h
 )
 
 target_include_directories(mirclientcpp

=== modified file 'src/miral/window_info.cpp'
--- src/miral/window_info.cpp	2017-08-21 14:18:55 +0000
+++ src/miral/window_info.cpp	2017-09-18 08:45:41 +0000
@@ -17,6 +17,7 @@
  */
 
 #include "miral/window_info.h"
+#include "window_info_defaults.h"
 
 #include "both_versions.h"
 
@@ -35,7 +36,40 @@
 {
     return optional_value.is_set() ? optional_value.value() : default_;
 }
-}
+
+unsigned clamp_dim(unsigned dim)
+{
+    return std::min<unsigned long>(std::numeric_limits<long>::max(), dim);
+}
+
+// For our convenience when doing calculations we clamp the dimensions of the aspect ratio
+// so they will fit into a long without overflow.
+miral::WindowInfo::AspectRatio clamp(miral::WindowInfo::AspectRatio const& source)
+{
+    return {clamp_dim(source.width), clamp_dim(source.height)};
+}
+
+miral::Width clamp(miral::Width const& source)
+{
+    return std::min(miral::default_max_width, std::max(miral::default_min_width, source));
+}
+
+miral::Height clamp(miral::Height const& source)
+{
+    return std::min(miral::default_max_height, std::max(miral::default_min_height, source));
+}
+}
+
+miral::Width  const miral::default_min_width{0};
+miral::Height const miral::default_min_height{0};
+miral::Width  const miral::default_max_width{std::numeric_limits<int>::max()};
+miral::Height const miral::default_max_height{std::numeric_limits<int>::max()};
+miral::DeltaX const miral::default_width_inc{1};
+miral::DeltaY const miral::default_height_inc{1};
+miral::WindowInfo::AspectRatio const miral::default_min_aspect_ratio{
+    clamp(WindowInfo::AspectRatio{0U, std::numeric_limits<unsigned>::max()})};
+miral::WindowInfo::AspectRatio const miral::default_max_aspect_ratio{
+    clamp(WindowInfo::AspectRatio{std::numeric_limits<unsigned>::max(), 0U})};
 
 struct miral::WindowInfo::Self
 {
@@ -71,16 +105,16 @@
     type{optional_value_or_default(params.type(), mir_window_type_normal)},
     state{optional_value_or_default(params.state(), mir_window_state_restored)},
     restore_rect{params.top_left().value(), params.size().value()},
-    min_width{optional_value_or_default(params.min_width())},
-    min_height{optional_value_or_default(params.min_height())},
-    max_width{optional_value_or_default(params.max_width(), Width{std::numeric_limits<int>::max()})},
-    max_height{optional_value_or_default(params.max_height(), Height{std::numeric_limits<int>::max()})},
+    min_width{optional_value_or_default(params.min_width(), miral::default_min_width)},
+    min_height{optional_value_or_default(params.min_height(), miral::default_min_height)},
+    max_width{optional_value_or_default(params.max_width(), miral::default_max_width)},
+    max_height{optional_value_or_default(params.max_height(), miral::default_max_height)},
     preferred_orientation{optional_value_or_default(params.preferred_orientation(), mir_orientation_mode_any)},
     confine_pointer(optional_value_or_default(params.confine_pointer(), mir_pointer_unconfined)),
-    width_inc{optional_value_or_default(params.width_inc(), DeltaX{1})},
-    height_inc{optional_value_or_default(params.height_inc(), DeltaY{1})},
-    min_aspect(optional_value_or_default(params.min_aspect(), AspectRatio{0U, std::numeric_limits<unsigned>::max()})),
-    max_aspect(optional_value_or_default(params.max_aspect(), AspectRatio{std::numeric_limits<unsigned>::max(), 0U})),
+    width_inc{optional_value_or_default(params.width_inc(), default_width_inc)},
+    height_inc{optional_value_or_default(params.height_inc(), default_height_inc)},
+    min_aspect(optional_value_or_default(params.min_aspect(), default_min_aspect_ratio)),
+    max_aspect(optional_value_or_default(params.max_aspect(), default_max_aspect_ratio)),
     shell_chrome(optional_value_or_default(params.shell_chrome(), mir_shell_chrome_normal))
 {
     if (params.output_id().is_set())
@@ -450,7 +484,7 @@
 
 void miral::WindowInfo::min_width(mir::geometry::Width min_width)
 {
-    self->min_width = min_width;
+    self->min_width = clamp(min_width);
 }
 
 auto miral::WindowInfo::min_height() const -> mir::geometry::Height
@@ -460,7 +494,7 @@
 
 void miral::WindowInfo::min_height(mir::geometry::Height min_height)
 {
-    self->min_height = min_height;
+    self->min_height = clamp(min_height);
 }
 
 auto miral::WindowInfo::max_width() const -> mir::geometry::Width
@@ -470,7 +504,7 @@
 
 void miral::WindowInfo::max_width(mir::geometry::Width max_width)
 {
-    self->max_width = max_width;
+    self->max_width = clamp(max_width);
 }
 
 auto miral::WindowInfo::max_height() const -> mir::geometry::Height
@@ -480,7 +514,7 @@
 
 void miral::WindowInfo::max_height(mir::geometry::Height max_height)
 {
-    self->max_height = max_height;
+    self->max_height = clamp(max_height);
 }
 
 auto miral::WindowInfo::userdata() const -> std::shared_ptr<void>
@@ -520,7 +554,7 @@
 
 void miral::WindowInfo::min_aspect(AspectRatio min_aspect)
 {
-    self->min_aspect = min_aspect;
+    self->min_aspect = clamp(min_aspect);
 }
 
 auto miral::WindowInfo::max_aspect() const -> AspectRatio
@@ -530,7 +564,7 @@
 
 void miral::WindowInfo::max_aspect(AspectRatio max_aspect)
 {
-    self->max_aspect = max_aspect;
+    self->max_aspect = clamp(max_aspect);
 }
 
 bool miral::WindowInfo::has_output_id() const

=== added file 'src/miral/window_info_defaults.h'
--- src/miral/window_info_defaults.h	1970-01-01 00:00:00 +0000
+++ src/miral/window_info_defaults.h	2017-09-18 08:45:41 +0000
@@ -0,0 +1,36 @@
+/*
+ * Copyright © 2017 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Alan Griffiths <[e-mail]>
+ */
+
+#ifndef MIR_WINDOW_INFO_DEFAULTS_H
+#define MIR_WINDOW_INFO_DEFAULTS_H
+
+#include "miral/window_info.h"
+
+namespace miral
+{
+Width  extern const default_min_width;
+Height extern const default_min_height;
+Width  extern const default_max_width;
+Height extern const default_max_height;
+DeltaX extern const default_width_inc;
+DeltaY extern const default_height_inc;
+WindowInfo::AspectRatio extern const default_min_aspect_ratio;
+WindowInfo::AspectRatio extern const default_max_aspect_ratio;
+}
+
+#endif //MIR_WINDOW_INFO_DEFAULTS_H

=== modified file 'src/miral/window_management_trace.cpp'
--- src/miral/window_management_trace.cpp	2017-08-21 14:18:55 +0000
+++ src/miral/window_management_trace.cpp	2017-09-18 08:45:41 +0000
@@ -17,6 +17,7 @@
  */
 
 #include "window_management_trace.h"
+#include "window_info_defaults.h"
 
 #include <miral/application_info.h>
 #include <miral/window_info.h>
@@ -133,18 +134,19 @@
         APPEND(name);
         APPEND(type);
         APPEND(state);
+        bout.append("size", info.window().size());
         if (info.state() != mir_window_state_restored) APPEND(restore_rect);
         if (std::shared_ptr<mir::scene::Surface> parent = info.parent())
             bout.append("parent", parent->name());
         bout.append("children", dump_of(info.children()));
-        if (info.min_width()  != Width{0}) APPEND(min_width);
-        if (info.min_height() != Height{0}) APPEND(min_height);
-        if (info.max_width()  != Width{std::numeric_limits<int>::max()}) APPEND(max_width);
-        if (info.max_height() != Height{std::numeric_limits<int>::max()}) APPEND(max_height);
-        if (info.width_inc()  != DeltaX{1}) APPEND(width_inc);
-        if (info.height_inc() != DeltaY{1}) APPEND(height_inc);
-        if (info.min_aspect() != miral::WindowInfo::AspectRatio{0U, std::numeric_limits<unsigned>::max()}) APPEND(min_aspect);
-        if (info.max_aspect() != miral::WindowInfo::AspectRatio{std::numeric_limits<unsigned>::max(), 0U}) APPEND(max_aspect);
+        if (info.min_width()  != miral::default_min_width)  APPEND(min_width);
+        if (info.min_height() != miral::default_min_height) APPEND(min_height);
+        if (info.max_width()  != miral::default_max_width)  APPEND(max_width);
+        if (info.max_height() != miral::default_max_height) APPEND(max_height);
+        if (info.width_inc()  != miral::default_width_inc)  APPEND(width_inc);
+        if (info.height_inc() != miral::default_height_inc) APPEND(height_inc);
+        if (info.min_aspect() != miral::default_min_aspect_ratio) APPEND(min_aspect);
+        if (info.max_aspect() != miral::default_max_aspect_ratio) APPEND(max_aspect);
         APPEND(preferred_orientation);
         APPEND(confine_pointer);
 

=== modified file 'tests/miral/CMakeLists.txt'
--- tests/miral/CMakeLists.txt	2017-09-14 09:22:16 +0000
+++ tests/miral/CMakeLists.txt	2017-09-18 08:45:41 +0000
@@ -40,6 +40,7 @@
     workspaces.cpp
     drag_and_drop.cpp
     client_mediated_gestures.cpp
+    window_info.cpp
 )
 
 target_link_libraries(miral-test

=== added file 'tests/miral/window_info.cpp'
--- tests/miral/window_info.cpp	1970-01-01 00:00:00 +0000
+++ tests/miral/window_info.cpp	2017-09-18 08:45:41 +0000
@@ -0,0 +1,61 @@
+/*
+ * Copyright © 2017 Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or 3 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Brandon Schaefer <[e-mail]>
+ */
+
+#include <miral/window_info.h>
+
+#include "mir_test_framework/process.h"
+
+#include <gtest/gtest.h>
+#include <gmock/gmock.h>
+
+using namespace miral;
+namespace mtf = mir_test_framework;
+
+namespace
+{
+static int a_successful_exit_function()
+{
+    return EXIT_SUCCESS;
+}
+}
+
+// Test for crash http://paste.ubuntu.com/25523431/
+TEST(WindowInfo, negative_window_size_does_not_divide_by_zero)
+{
+    auto p = mtf::fork_and_run_in_a_different_process(
+        [] {
+            Window window;
+            WindowSpecification params;
+
+            Point p{0, 0};
+            Size  s{-300, -300};
+
+            params.name()     = "";
+            params.top_left() = p;
+            params.size()     = s;
+
+            WindowInfo info(window, params);
+
+            info.min_width(s.width);
+            info.min_height(s.height);
+
+            info.constrain_resize(p, s);
+        }, a_successful_exit_function);
+
+    EXPECT_TRUE(p->wait_for_termination().succeeded());
+}